MANEJO OPERATIVO DEL TUMOR RECTAL

Indications Transanal Excision of Tumor Stage T1 tumors: Mobile and < 4 cm in diameter. Involving < 40% of the rectal wall circumference. Located within 6 cm of the anal verge. Well or moderately differentiated histology only. Absence of vascular and lymphatic invasion. No evidence of nodal involvement on preoperative rectal ultrasound or MRI. Low Anterior Resection (LAR) with Total Mesorectal Excision Malignant lesion of the rectum diagnosed by evaluation of a tissue biopsy specimen obtained within 2 cm of the anal sphincter in moderately or well-differentiated tumors or within 5 cm for poorly differentiated tumors. Abdominoperineal Resection (APR) with Total Mesorectal Excision Malignant lesion of the rectum diagnosed by evaluation of a tissue biopsy specimen obtained < 2 cm from the anal sphincter for moderately or well-differentiated tumors or < 5 cm for poorly differentiated tumors.

Contraindications Transanal Excision of Tumor Tumors stage greater than T1N0M0. Fixed tumors. Tumors > 4 cm in diameter or involving > 40% of the circumference of the rectal wall. Tumors located > 6 cm from the anal verge. Tumors with poorly differentiated histology or angiolymphatic invasion, or those that show evidence of nodal involvement on preoperative rectal ultrasound or MRI. LAR with Total Mesorectal Excision Malignant lesion of the rectum diagnosed by evaluation of a tissue biopsy specimen obtained < 2 cm from the anal sphincter for moderately or well-differentiated tumors or < 5 cm for poorly differentiated tumors. APR with Total Mesorectal Excision Malignant lesion of the lower rectum diagnosed by evaluation of a tissue biopsy specimen showing local invasion into the pelvic sidewall or pelvis that could benefit from neoadjuvant treatment to facilitate possible curative resection.

Informed Consent Transanal Excision of Tumor Expected Benefits Removal of tumor with preservation of anus. Avoidance of radical surgery. Potential Risks Bleeding requiring reoperation. Rectal stricture. Need for further resection based on pathologic findings. Fistula to prostate or vagina. Injury to the urethra for distal anterior tumors in men. LAR or APR with Total Mesorectal Excision Expected Benefits Treatment of rectal cancer. Potential prevention of colonic obstruction, tenesmus, and invasion of adjacent pelvic structures. Potential Risks Bleeding requiring reoperation from presacral or splenic injuries (LAR or APR) or from the anastomosis (LAR). Infection, including intra-abdominal or pelvic abscesses resulting from anastomotic leaks (LAR) or infected intra-abdominal or pelvic fluid collections (LAR or APR). Fistula formation from anastomotic leak (LAR). Postoperative ileus (LAR or APR). Ureteral injury (LAR or APR). Need for a permanent or temporary stoma (LAR). Bladder or sexual dysfunction (LAR or APR). Fecal incontinence (LAR). Clustering of bowel movements (LAR).

Equipment Transanal Excision of Tumor Self-retaining (Ferguson) anoscope. Lone Star retractor (for more proximal lesions). LAR or APR with Total Mesorectal Excision Self-retaining retractors. Bookwalter abdominal retractor with a lighted St. Mark's retractor. Lone Star retractor (for perineum). Handheld lighted St. Mark's retractor and long instruments (crucial for delicate dissection in the pelvis). Gastrointestinal anastomosis (GIA) stapler. End-to-end anastomosis (EEA) stapler (LAR). Thoracoabdominal (TA) stapler (LAR).

Patient Preparation Clearance of bowel for synchronous lesions by colonoscopy. CT scan of the chest, abdomen, and pelvis to evaluate for metastatic disease of the lungs, liver, or peritoneum. Endorectal ultrasound or endorectal MRI for local staging (T and N staging). Patients with uT1N0 tumors may be appropriate candidates for transanal excision. Patients with uT3NX or uTXN+ disease should be considered for possible neoadjuvant chemoradiation therapy. Consider preoperative tattooing of the lesion with permanent ink, especially if the lesion is small or the patient will receive neoadjuvant chemoradiotherapy. Preoperative carcinoembryonic antigen level. Nothing by mouth the evening before surgery. Mechanical bowel preparation according to surgeon's preference. Preoperative antibiotics and preoperative subcutaneous heparin. Anesthesiology consultation as needed. Stoma marking by an enterostomal therapist for patients undergoing LAR or APR.

Patient Positioning Transanal Excision of Tumor For posterior lesions, the patient should be in a supine lithotomy position in gentle Trendelenburg using well-padded stirrups. For anterior lesions, the prone jackknife position is preferred. Sequential pneumatic compression devices should be applied. LAR or APR with Total Mesorectal Excision The patient should be in a supine lithotomy position in gentle Trendelenburg using well-padded stirrups. Sequential pneumatic compression devices should be applied. A Foley catheter and nasogastric or orogastric tube should be placed, especially if mobilization of the splenic flexure is contemplated. Consideration should also be given to the placement of a left ureteral stent if a difficult pelvic dissection is anticipated.

Procedure Transanal Excision of Tumor Regional anesthesia may be adequate, although general anesthesia is sometimes required. A self-retaining retractor is placed and a 1:100,000 epinephrine solution is infiltrated into the submucosa to facilitate dissection. Figure 24–1: Stay sutures are placed circumferentially 1 cm from the gross margin of the lesion. Figure 24–2: Full-thickness excision of the lesion is performed down to the level of perirectal fat using electrocautery. The specimen is carefully marked to delineate the correct orientation for the pathologist. Figure 24–3: The defect in the rectal wall is closed transversely with absorbable suture. Proctoscopic examination of the rectum is performed at the conclusion of the procedure to ensure patency of the rectum. Figure 24–1 Figure 24–2 Figure 24–3 LAR or APR with Total Mesorectal Excision General anesthesia is required. The patient should be in the lithotomy position with the legs elevated at approximately 15 degrees and spread at 45 degrees. Positioning of the anus and buttocks at the end of the table is important for access. A median laparotomy incision from the pubis symphysis to above the umbilicus is performed. For an LAR or APR, a self-retaining retractor is placed and the small intestine is retracted superiorly and to the right under a moistened towel. The left colon is freed from its lateral peritoneal attachments along the avascular line of Toldt, and the splenic flexure is mobilized (see Chapter 23) as needed for a tension free anastomosis. The peritoneum of the pelvic colon is opened using electrocautery. Care must be taken to identify the ureters, on the left in particular. The left ureter is identified as it crosses the pelvic brim over the left common iliac artery. Especially in patients with a significant amount of adipose tissue, widely encircling the ureter with a vessel loop can aid in safe mobilization of the distal rectum. The inferior mesenteric artery is identified at its origin and suture-ligated. The distal descending colon is then divided with a GIA-60 stapling device at least 5 cm proximal to the tumor. Figure 24–4: The distal rectum is then sharply mobilized posteriorly to remove the mesorectum intact with its fascial envelope (see also Figures 24–7A and 24–7B). The bladder is retracted superiorly and the anterior rectal wall is separated from the seminal vesicles and the posterior capsule of the prostate in a man. The lateral dissection encompasses the lateral peritoneal reflections, and middle hemorrhoidal vessels are ligated and divided. Figure 24–5: The proximal rectum is then clamped and a linear stapling device is applied across the rectum at least 2 cm distal to the tumor. The proximal rectum is divided and the specimen is removed. Figure 24–6A, B: Creation of the stapled LAR anastomosis. The staple line of the descending colon is opened and a nonabsorbable purse-string suture is placed. The anvil of a circular stapler is placed within the descending colon through the purse-string suture, and the suture is tied. The assistant then passes the circular stapler through the anus, deploying the "spike" just anterior to the staple line on the rectum. The anastomosis is completed as the surgeon marries the anvil placed in the end of the divided descending colon to the stapler exiting the rectum. The surgeon guides the end of the stapler together, taking care that no other tissue (ie, bladder or vagina) is intervening in the anastomosis, and the assistant fires the stapler. The rings of tissue ("donuts") are inspected for any defect. The assistant then inspects the integrity of the anastomosis by insufflating the rectum using a rigid sigmoidoscope, while the surgeon manually occludes the distal colon with the anastomosis submerged in sterile saline. The presence of any bubbling from the anastomosis suggests an anastomotic leak. Figure 24–4 Figure 24–5 Figure 24–6A–B Total Mesorectal Excision Care must be taken with lower lying rectal cancers to perform a total mesorectal excision to prevent leaving nodal tumor deposits behind. The superior hemorrhoidal artery is identified and ligated. Figure 24–7A-C: There should be wide incision at the peritoneal reflection and sharp division of the Waldeyer's fascia posterior to the fascia propria of the rectum, as well as incision of Denonvilliers' fascia and separation of the rectal wall from the seminal vesicles and the posterior capsule of the prostate anteriorly. Figure 24–8A, B: The correct and incorrect dissection planes for total mesorectal excision are depicted. Figure 24–7A–C Figure 24–8A–B Coloanal Anastomosis If it is not possible to obtain a distal rectal margin of at least 2 cm, a coloanal anastomosis may be contemplated. Figure 24–9A-C: The distal rectum is divided proximal to the dentate line following rectal dissection and total mesorectal incision. A 5–6-cm colonic J pouch can be fashioned using a GIA stapler. The end-to-side J pouch coloanal anastomosis is then created by sewing the full-thickness colon to the mucosa and internal sphincter of the anus. Absorbable sutures are used to create this anastomosis, and the colotomy created to allow admission of the GIA stapler when creating the J pouch is used for the anastomosis (Figure 24–9A, Figure 24–9C). If there is insufficient length for a colonic J pouch, an end-to-end anastomosis can be fashioned using a circular stapler or hand-sewn anastomosis as outlined above (Figure 24–9B, C). Figure 24–9A Figure 24–9B–C Abdominoperineal Resection for Low-Lying Rectal Cancers This procedure requires the same attention to obtaining adequate radial margins via total mesorectal excision. Figure 24–10: The sigmoid artery proximal to the takeoff of the superior hemorrhoidal artery is ligated. Figure 24–11A, B: The distal margin of resection should include the levators, as visualized from the perineal portion of the operation. Figure 24–12: The closure of the perineal incision should be in layers, beginning with the levators followed by the deep tissues and skin. Drains are placed in the deep space and are brought out through the lower abdominal wall. Figure 24–10 Figure 24–11A–B Figure 24–12

Postoperative Care Early ambulation is encouraged and diet is advanced as soon as tolerated. Patients requiring abdominal incision receive epidural analgesia and are transitioned to oral pain medications as soon as they can tolerate solids. Patients with ileostomies may require aggressive management of fluid status after the resumption of bowel function. We promote aggressive isotonic liquid consumption by the patient, with avoidance of caffeine and chocolate, and prefer first to use fiber bulking agents, followed by the addition of the antimotility agent loperamide. Daily examination of the perineal wound is mandatory following APR, and sitting should be discouraged for the first 5 postoperative days. Walking, however, should be aggressively encouraged. Pelvic drains are generally removed on postoperative day 5.

Potential Complications Transanal Excision of Tumor As excision of the rectal wall is carried out below the peritoneal reflection, intra-abdominal leak is generally not a problem. Deep space infections can occur and should be treated by local drainage. More commonly, pathologic evaluation reveals more extensive disease than was appreciated preoperatively, necessitating further local or more radical resection. LAR and APR with Total Mesorectal Excision Postoperative ileus is common, usually lasting 2–3 days and rarely requiring nasogastric decompression. Colonic ileus lasting longer than 2–3 days after LAR should prompt suspicion of an anastomotic hematoma, mechanical obstruction, or peritonitis associated with an anastomotic leak. Anastomotic leak is a potentially devastating complication following LAR and typically occurs 5–7 days following resection. Fever, leukocytosis, ileus, and distention may be early signs of a leak. Peritonitis mandates exploration with proximal diversion if a leak is discovered. More subtle clinical presentations may require imaging with water-soluble contrast enema for identification. Intra-abdominal abscesses from breaks in surgical technique may require intravenous antibiotics, bowel rest, and percutaneous drain placement. Splenic injury can occur when mobilization of the splenic flexure is necessary to perform a tension-free anastomosis (LAR), or as necessary for the colon to be easily brought up for end colostomy (APR). Ureteral injury can result from altered rectosigmoid anatomy associated with malignancy, inflammation, and neoadjuvant radiotherapy. Bladder or sexual dysfunction can occur due to injury of the sympathetic or parasympathetic nerves in the pelvis.

Pearls and Tips Transanal Excision of Tumor Pin the specimen out on suture card or cardboard and deliver it to the pathologist with correct orientation. Perform proctoscopy at the end of the procedure to ensure that the rectal lumen has not been sutured closed. Patients are usually hospitalized overnight for observation. Fever > 38.8°C is not uncommon in the immediate postoperative period, but if fever continues through the first postoperative night, blood and urine cultures as well as plain films of the chest should be ordered to evaluate for other, treatable sources of infection. LAR and APR with Total Mesorectal Excision For low rectal anastomosis, fill the pelvis with sterile saline and insufflate the rectal stump before reanastomosis with the circular stapler. If a leak is identified in the linear staple line on the rectum, posterior dissection should extend posteriorly to the level of the coccyx to identify the site of leakage. The circular stapler can then be brought out through the defect, a purse-string suture placed around the spike, and the purse-string suture excluded after firing the circular stapler. During perineal dissection, maintain constant attention to palpation of the Foley catheter to avoid inadvertent urethral injury.

References Chang AE, Morris AM. Colorectal Cancer. In: Mulholland MW, Lillemoe KD, Doherty GM, et al, eds. Greenfield's Surgery: Scientific Principles & Practice, 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:1103–1128. Huang EH. Complications of Appendectomy and Colon and Rectal Surgery. In: Mulholland MW, Doherty GM, eds. Complications in Surgery. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:498–522.